An island off Costa Rica will soon be the world's most ambitious theme park--a dinosaur preserve. A visionary financier's biotechnology company has succeeded in cloning these extinct reptiles. Fifteen different species, presumably incapable of breeding, are now placidly roaming around, but Jurassic Park's resident mathematician, an expert in chaos theory, predicts that the animals' behavior is inherently unstable. When a rival genetics firm attempts to steal frozen dinosaur embryos, things go haywire. Two cute American kids, eight-year-old Tina and 11-year-old Tim, a safari guide from Kenya and a Denver paleontologist set things aright--almost. Though the dinosaurs here are more interesting than the people, Crichton ( The Andromeda Strain ) ingeniously interweaves details of genetic engineering, computer wizardry and current scientific controversy over dinosaurs to fashion a scary, creepy, mesmerizing techno-thriller with teeth. It can be read as a thought-provoking fable about technological hubris and the hazards of bioengineering. 150,000 first printing; Literary Guild main selection; movie rights sold to Steven Spielberg/Universal Pictures . (Nov.)